Collapsible chair with tensioned seat

ABSTRACT

A collapsible chair ( 10 ) has a first ( 110 ) and second ( 112 ) front leg, a rear leg ( 120 ), a seat support rod ( 130 ), and a backrest is attached to the front legs. The legs and the seat support rod are coupled via cross braces ( 140, 150 ) such that the seat support rod pivots in one direction while the rear leg pivots in the opposite direction when the front legs are approximated to each other. Preferred chairs comprise a seat that is tensioned when the front legs move apart, and the seat remains substantially tensioned when the seat supports a person.

FIELD OF THE INVENTION

The field of the invention is collapsible furniture.

BACKGROUND OF THE INVENTION

Folding chairs are relatively popular, because they can be stored withconsiderably reduced space requirements when compared to non-foldingchairs. Nevertheless, folding chairs still require relatively largespace, since the dimension of the folding chair is generally reducedonly along one space coordinate (e.g., reduced length). To furtherreduce the space requirement, collapsible chairs have been developed, inwhich further size reduction is achieved by folding the chair along atleast two space coordinates (e.g., length and width). Various collapsingchairs are known in the art.

For example, Cook et al. describes in U.S. Pat. No. 5,921,621 acollapsible chair with a foldable backrest, in which the chair has fourlegs that support the corners of a flexible square seat. The legs aremovably attached to each other at about their respective midpoints, andthe seat is collapsed in width and depth by turning the legs around themidpoint. While Cooks chair is relatively easy to unfold and collapse,Cooks chair provides relatively little stability and is prone to tippingover.

Improved stability can be achieved by including slidable cross barsbetween the legs as described in U.S. Pat. No. 6,082,813 to Chen andU.S. Pat. No. 5,984,406 to Lee. Chen's chair advantageously collapses toa relatively compact form. However, the position of the back support islimited to a vertical position, which may not be comfortable over aprolonged period. On the other hand, Lee's chair provides an angledbackrest, although it lacks a seat support entirely.

In addition to the problems of the collapsible chairs mentioned above,all or almost all of the known collapsible chairs suffer from a commondisadvantage in that the seat will loose tension once the seat supportsthe weight of a person. Moreover, where known chairs are collapsible ina single motion, such chairs do typically fail to provide a seat supportrod onto which the seat can be tensioned. Alternatively, where knownchairs have a pair of seat support rods, such chairs generally requireat least two folding motions (e.g., one motion in which the seat isfolded upwards followed by one motion in which the seat is folded in aside-to-side movement). Therefore, there is a need to provide improvedmethods and apparatus for collapsible chairs.

SUMMARY OF THE INVENTION

The present invention is directed to a collapsible chair that can becollapsed in a single motion, wherein the chair includes a tensionedseat coupled to a pair of seat support rods. In particular, thecollapsible chair has a pair of front legs, rear legs, and a pair ofseat support rods wherein a backrest is coupled to the front legs, and atensioned seat is coupled to the seat support rods. The front legs, therear legs, and the seat support rods are coupled in a manner such thatthe chair collapses in a single movement in which the front legsapproximate each other when the rear legs and the seat support rodspivot towards the front legs.

In one aspect of the inventive subject matter, contemplated chairsinclude a first front leg and a second front leg, a rear leg, a seatsupport rod, and a backrest attached to the front legs. A first crossbrace is rotatably coupled to the rear leg and slidably coupled to thefirst front leg, and a second cross brace is rotatably coupled to thesecond front leg and slidably coupled to the seat support rod. The seatsupport rod in contemplated chairs pivot in a first direction relativeto the first front leg and the rear leg pivots in a direction oppositeto the first direction when the first and second front legs approximateeach other.

In a preferred aspect of the inventive subject matter, the chair has asecond seat support rod, and a seat is attached to the seat supportrods, wherein the seat is tensioned when the first and the second frontlegs move apart, and wherein the seat remains substantially tensionedwhen the seat supports a person.

In another aspect of the inventive subject matter, the legs and seatsupport are manufactured from a metal, preferably aluminum, and the seatand backrest may be coupled together and are fabricated from a weatherresistant material, preferably a synthetic polymer, and more preferablyfrom Nylon.

In a further aspect of the inventive subject matter, a method ofimparting collapsibility into a chair comprise one step in which a firstand a second front leg, a first and a second seat support rod, and afirst and a second rear leg are provided. In a further step, the firstand the second front legs are coupled with a first cross brace, whereinthe first cross brace is rotatably attached to the first front leg andslidably attached to the second front leg, and the first front leg andthe second seat support rod are coupled with a second cross brace,wherein the second cross brace is rotatably attached to the first frontleg and slidably attached to the second seat support rod. In a furtherstep, the first front leg is rotatably coupled to the first rear leg andthe first seat support rod, while the first seat support rod is slidablycoupled to the first rear leg.

Various objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of preferred embodiments of the invention, along with theaccompanying drawings, in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a collapsible chair without seat andbackrest.

FIG. 2 is a perspective view of the collapsible chair of FIG. 1 withattached seat and backrest.

FIG. 3 is a perspective view of the collapsible chair of FIG. 1 incollapsed configuration.

FIG. 4 is a perspective view of another collapsible chair with tensionedseat and backrest.

FIG. 5 is a perspective view of the collapsible chair of FIG. 4 withouttensioned seat and backrest.

DETAILED DESCRIPTION

It is generally contemplated that a collapsible chair includes atensioned seat coupled to a pair of seat support rods, and the chair canbe collapsed in a single motion. Contemplated chairs have a pair offront legs, rear legs, and a pair of seat support rods wherein abackrest is coupled to the front legs, and a tensioned seat is coupledto the seat support rods. The front legs, the rear legs, and the seatsupport rods are coupled in a manner such that the chair collapses in asingle movement in which the front legs approximate each other when therear legs and the seat support rods pivot towards the front legs.

In FIG. 1, a collapsible chair 100 has a first front leg 110 and asecond front leg 112, a rear leg 120, a seat support rod 130, and abackrest (not shown in FIG. 1, see FIG. 2). A first cross brace 140 isrotatably coupled to the rear leg and slidably coupled to the firstfront leg 110, and a second cross brace 150 is rotatably coupled to thesecond front leg 112 and slidably coupled to the seat support rod 130;The backrest is attached to the first and second front legs 110 and 112,wherein the seat support rod 130 pivots in a first direction relative tothe first front leg 110 and the rear leg 120 pivots in a directionopposite to the first direction when the first and second front legs 110and 112 approximate each other.

In FIG. 2, the collapsible chair 200 further has a backrest 260 attachedto the first and second front legs 210 and 212, and a seat 270 isattached to the seat support rods (not visible in FIG. 2, see FIG. 1).FIG. 3 depicts the collapsible chair 300 of FIG. 1 in a collapsedconfiguration. An alternative embodiment of the inventive subject matteris depicted in FIG. 4, in which a collapsible chair is depicted with atensioned seat. In FIG. 5, the chair of FIG. 4 is shown without thetensioned seat.

It is contemplated that the seat and the backrest are fabricated from aweather resistant material, preferably a woven synthetic polymer (e.g.,Nylon) and is uniformly colored (e.g., blue). Particularly preferredseats have a width of about 21 inches and an overall length of about 24inches. However, it should be appreciated that various alternativematerials, colors, and sizes are also appropriate.

For example, alternative materials may include natural and syntheticfabrics and all reasonable combinations thereof. Contemplated materialsmay further be woven or non-woven and particularly contemplatedmaterials include polyester, polyvinyl chloride, cotton, hemp, and wool.With respect to the color, it is contemplated that suitable colors neednot be restricted to uniform color, but appropriate colors may alsoinclude color patterns, prints, or no color at all. While it isgenerally preferred that the chair according to the inventive subjectmatter is sized and dimensioned to fit an average adult person, it isalso contemplated that appropriate chairs may also accommodate a child,a smaller- or larger-than-average adult, or more than a single person.Therefore, alternative chairs may have dimensions that are wider than 21inches, and suitable widths include 21–24, 24–30, and 30–40 inches, andwider, but also 18–21, 14–18, and 8–14 inches, and narrower. Likewise,the length of appropriate seats may vary between 20–42, 15–10, and 12–15inches and less, but also between 24–27, 27–30, and more. It shouldfurther be appreciated that contemplated seats may also be tapered fromthe front end to the back end, or vice versa.

With respect to the backrest it is contemplated that the backrest isfabricated from the same material as the seat, and that the backrest isremovably or permanently coupled to the seat (e.g., sewed, coupled witha zipper, etc.) Thus, it is preferred that the backrest has a width ofabout 21 inches. A preferred height of the backrest is about 18 inches.With respect to the material and color, it is contemplated that the sameconsiderations as for the seat apply. It is further contemplated thatthe width and height of suitable backrests may vary, and that width andheight will depend among other things on the person's size and thenumber of persons to be seated in the chair. Thus, alternative backrestsmay have a width between 18–12 inches and less, but also between 18–22and more. Similarly, contemplated backrests may have a height between12–18 inches and less, but also between 18–25 inches and more.

It is generally contemplated that the seat and the backrest may becoupled to the legs and seat support rods in numerous ways, includingtemporary and permanent coupling. Temporary couplings includehook-and-loop type fasteners, snaps, buckles, slidable elements (e.g., apouch slidably coupled to a post, a ring slidably coupled to a rod,etc.), and threadbly securable elements (e.g., laces threaded throughrings). Permanent couplings include sewed or glued elements. Forexample, the backrest may permanently coupled to the chair via a rivet.On the other hand, the front end of the seat may be temporarily coupledto the front legs via ring-shaped openings slided over the top ends ofthe front legs. It is further, particularly preferred that the seat andthe backrest are coupled together.

It should further be appreciated that the attachment of the seat and/orthe backrest to the chair may be directly or indirectly attached. Asused herein, the term “direct” attachment means that the seat and/or thebackrest are in immediate contact with the supporting structure, whereasthe term “indirect” means that an additional element connects the seatand/or backrest with the supporting structure. For example, the seat maybe directly attached to the seat support rods via a slidable pouch.Alternatively, the seat may be indirectly coupled to the seat supportrods via a ring-shaped opening in the seat that slidably engages withthe rods.

With respect to the legs, seat support rods, and cross braces ofcontemplated chairs, it should be appreciated that all of these elementsmay be manufactured from various materials, including metals, metalalloys, natural and synthetic polymers, and any reasonable combinationthereof. However, it is preferred that the legs, seat support rods, andcross braces are manufactured from black anodized aluminum tubing with awall strength of about 1/32 inch and an outer diameter of approximately½ inch. Preferred alternative materials include stainless steel,fiberglass, and wood.

Where one of the legs, seat support rods, and cross braces is pivotablycoupled to another one of the legs, seat support rods, and cross braces,it is generally contemplated that all known manners of couplingrotatably are suitable for use in conjunction with the teachingspresented herein. For example, appropriate manners of coupling rotatablyinclude coupling of two elements via a common axis, coupling via a hingewherein the hinge may or may not have a slidable connection to anotherelement, coupling via a ball bearing, etc. Similarly, where one of thelegs, seat support rods, and cross braces is slidably coupled to anotherone of the legs, seat support rods, and cross braces, all known slidablecouplings are contemplated to be appropriate, and include a slidingsleeve, slide rails, guiding rings, etc.

In a preferred aspect, a collapsible chair has two front legs, two rearlegs, and two seat support rods, wherein a first pair of cross bracescouples the front legs to the seat support rods, and a second pair ofcross braces couples the front legs to the rear legs. It is particularlypreferred, that all of the front legs, rear legs and seat support rodsare coupled through the cross braces in a manner that allows collapsingthe chair in a single movement, i.e., that the front legs approximateeach other and the front end of the seat support rods rotates towardsone end of the front legs, when the rear legs pivot towards the otherend of the front legs. In preferred configurations, the seat support rodpivots upwardly and the back leg pivots downwardly relative to the firstfront leg, when the chair is unfolded in an extended configuration. Asviewed from another perspective, it is preferred that the seat andbackrest fold when the front legs approximate.

Thus, a method of imparting collapsibility into a chair has one step inwhich a first and a second front leg, a first and a second seat supportrod, and a first and a second rear leg are provided. In another step,the first and the second front leg are coupled with a first cross brace,wherein the first cross brace is rotatably attached to the first frontleg and slidably attached to the second front leg. The first front legis coupled with the second seat support rod with a second cross brace,wherein the second cross brace is rotatably attached to the first frontleg and slidably attached to the second seat support rod. In a furtherstep, the first front leg is rotatably coupled to the first rear leg andthe first seat support rod, and in yet another step the first seatsupport rod is slidably coupled to the first rear leg.

It should be recognized that such preferred coupling may be realized invarious configurations. In an exemplary configuration of preferredchairs, the front leg on one side of the chair is coupled to the seatsupport rod on the other side of the chair via a cross brace, whereinthe cross brace is on one end rotatably coupled to the front leg, and onthe other end rotatably and slidably coupled to the seat support rod.The front leg on the other side of the chair is coupled to the seatsupport rod on the opposite side of the chair via a cross brace, whereinthe cross brace is on one end rotatably coupled to the front leg, and onthe other end rotatably and slidably coupled to the seat support rod.Both of the front legs are rotatably coupled to the respective seatsupport rods, wherein the coupling point to the front leg is located inabout the middle of the length of the front leg, and wherein thecoupling point to the seat support rod is located in about a third ofthe length of the seat support rod. Each of the seat support rods isfurther rotatably and slidably coupled to the respective rear leg,wherein the point of coupling is approximately at the rear end (relativeto the seat) of the seat support rod. Both of the rear legs arerotatably coupled near their upper ends to the front leg, wherein thepoint of coupling is above the coupling point of the front leg to theseat support rod. Another set of cross braces (e.g., two cross braces)couples the upper end of the front legs with the lower end of the rearlegs, wherein the coupling between the cross brace and the rear leg isrotatable, and the coupling between the cross brace and the rear leg isrotatable and slidable.

However, it should be appreciated that in alternative aspects of theinventive subject matter the number of legs, and/or seat supports mayvary considerably. For example, where the chair is sized and dimensionedto accommodate more than one person, three, four, or more legs, and/orseat supports may be included. On the other hand, where stability of theseat is particularly desirable, three or more seat support rods may beincluded in a chair with two front legs and two rear legs. Likewise, thenumber of cross braces may vary, and while some chairs may have only onepair of cross braces, other chairs may include three, four, or morecross braces.

Furthermore, it should be appreciated that the coupling may verydepending on the particular configuration of contemplated chairs. Forexample it is contemplated that all of the couplings may be rotatableand slidable. Alternatively, where slidable couplings are lessdesirable, alternative couplings may be employed and suitable couplingsespecially include temporary couplings such as snap connectors,connectors that are secured with a pin or other removable element, etc.In still further alternative aspects of the inventive subject matter,the coupling may be done via an intermediate rod, that rotatably couplestwo elements together (e.g., the intermediate rod that couples the frontleg to the rear leg in FIG. 2).

It should be especially appreciated that in contemplated configurationsof collapsible chairs, the seat is tensioned when the first and thesecond front legs move apart, and that the seat remains substantiallytensioned when the seat supports a person. The term “tensioned seat”means that the seat is substantially level when the chair is in the openconfiguration, wherein the term “substantially level” means that thevertical distance between any point of the seat and the seat support rodis no more than one 0.75 inch, more preferably no more than 0.5 inch,and most preferably no more than 0.25 inch. The term “openconfiguration” refers to the configuration of the collapsible chair inwhich the front legs have a maximum distance from each other when thechair is opened using reasonable force (i.e. without damaging themechanical structure). The term “remains substantially tensioned” meansthat the vertical distance between the lowest point of the seat and theseat support rod increases no more than one inch, preferably no morethan 0.75 inch, more preferably no more than 0.5 inch, and mostpreferably no more than 0.25 inch. Thus, it should be recognized thatthe tension of the seat is predominantly determined by the firmness ofthe material of the seat.

While not whishing to be bound by a particular theory, it iscontemplated that the tension in the seat remains substantiallytensioned due to mechanically coupling an approximating movement of theseat support rods with a simultaneous movement of at least one of therear legs relative to the front leg and a movement of the front legsrelative to each other. Viewed from another perspective, it should berecognized that while all or almost all of the prior art chairs with aseat support rod require at least two separate folding operations tocollapse the chair, contemplated collapsing chairs are folded in asingle movement (comparably to the collapsing of an umbrella). Moreover,it should be recognized that contemplated modes of coupling the frontleg with the rear leg and the seat support rod prevent loss of tensionof the seat when a person is supported by the chair.

Thus, specific embodiments and applications of collapsible chairs havebeen disclosed. It should be apparent, however, to those skilled in theart that many more modifications besides those already described arepossible without departing from the inventive concepts herein. Theinventive subject matter, therefore, is not to be restricted except inthe spirit of the appended claims. Moreover, in interpreting both thespecification and the claims, all terms should be interpreted in thebroadest possible manner consistent with the context. In particular, theterms “comprises” and “comprising” should be interpreted as referring toelements, components, or steps in a non-exclusive manner, indicatingthat the referenced elements, components, or steps may be present, orutilized, or combined with other elements, components, or steps that arenot expressly referenced.

1. A collapsible chair, comprising: a first front leg and a second frontleg, a pair of rear legs, a pair of seat support rods, and a backrest; afirst cross brace rotatably coupled to the pair of rear legs androtatably coupled to the first and second front legs, and a second crossbrace rotatably coupled to the first and second front legs and rotatablycoupled to the pair of seat support rods; wherein the pair of seatsupport rods are rotatably and slidably coupled to the rear legs suchthat the rear legs approximate the front legs as the front legsapproximate each other; and a backrest attached to the first and secondfront legs.
 2. The collapsible chair of claim 1 wherein the seat istensioned when the first and the second front legs move apart, andwherein the seat remains substantially tensioned when the seat supportsa person.
 3. The collapsible chair of claim 2 wherein the seat isfabricated from a weather resistant material.
 4. The collapsible chairof claim 2 wherein the seat is removably attached to the pair of seatsupport rods.
 5. The collapsible chair of claim 2 wherein the seat iscoupled to the backrest.
 6. The collapsible chair of claim 1 wherein thebackrest is removably attached to the first and second front legs. 7.The collapsible chair of claim 1 wherein the seat support rod pivotsupwardly and the back leg pivots downwardly relative to the first frontleg, when the chair is unfolded in an extended configuration.
 8. Amethod of imparting collapsibility into a chair, comprising: providing afirst front leg and a second front leg, a pair of rear legs, a pair ofseat support rods, and a backrest; rotatably coupling a first crossbrace to the pair of rear legs and further rotatably coupling the firstcross brace to the first and second front legs; rotatably coupling asecond second cross brace to the first and second front legs and furtherrotatably coupling the second cross brace to the pair of sear supportrods; wherein the pair of seat support rods are rotatably and slidablycoupled to the rear legs such that the rear legs approximate the frontlegs as the front legs approximate each other; and coupling a backrestto the first and second front legs.
 9. The method of claim 8 furthercomprising a step of coupling a set to the seat support rods.
 10. Themethod of claim 9 wherein the seat is contiguous with the backrest.